The present invention relates to processes for automatically compensating the mechanical errors in devices used for measuring the gradient of a magnetic field, known under the name of magnetic gradient meters. It also relates to devices for implementing this process and the gradient meters which are equipped thereby.
It is known to measure the gradient of the component of a magnetic field in a given direction along an axis Y at a point on this axis by placing two directional measuring probes, or magnetometers, on the axis, on each side of this point, and separated by a small distance .delta.Y. If .delta.Hy is the difference in the measurements of the two probes, the value of the gradient to be measured is given by; ##EQU1##
In addition to the causes of errors due to the defects of the probes themselves taken individually and to the associated electronic equipment, an important source of error is the lack of colinearity of the measuring axes of the two probes.
The inventor of the present invention, in his French patent application No. 83,1571 filed on the Oct. 4, 1983, has proposed constructing an integrated magnetic gradient meter in which the measuring axis is defined by a single light beam which passes through a thin layer in its thickness, which intrinsically eliminates alignment errors.
Such a device is however, not adapted to all the measuring configurations, particularly when the distance .delta.y is not very small. Furthermore, it is often desired, for reasons of cost, to be able to associate currently available magnetometers together so as to form a gradient meter.